# Save Mode

Save operations can optionally take a SaveMode, that specifies how to handle existing data if present. It is important to realize that these save modes do not utilize any locking and are not atomic. Additionally, when performing an Overwrite, the data will be deleted before writing out the new data.

#### SaveMode.ErrorIfExists (default)

When saving a DataFrame to a data source, if data already exists, an exception is expected to be thrown.

#### SaveMode.Append

When saving a DataFrame to a data source, if data/table already exists, contents of the DataFrame are expected to be appended to existing data. 

#### SaveMode.Overwrite

Overwrite mode means that when saving a DataFrame to a data source, if data/table already exists, existing data is expected to be overwritten by the contents of the DataFrame.

#### SaveMode.Ignore

Ignore mode means that when saving a DataFrame to a data source, if data already exists, the save operation is expected not to save the contents of the DataFrame and not to change the existing data. This is similar to a CREATE TABLE IF NOT EXISTS in SQL.


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